Transcriptomics Reveal Several Novel Viruses from Canegrubs (Coleoptera: Scarabaeidae) in Central Queensland, Australia

Insights into the RNA Virome of the Corn Leafhopper Dalbulus maidis, a Major Emergent Threat of Maize in Latin America

The maize leafhopper (Dalbulus maidis) is a significant threat to maize crops in tropical and subtropical regions, causing extensive economic losses. While its ecological interactions and control strategies are well studied, its associated viral diversity remains largely unexplored. Here, we employ high-throughput sequencing data mining to comprehensively characterize the D. maidis RNA virome, revealing novel and diverse RNA viruses. We characterized six new viral members belonging to distinct families, with evolutionary cues of beny-like viruses (Benyviridae), bunya-like viruses (Bunyaviridae) iflaviruses (Iflaviridae), orthomyxo-like viruses (Orthomyxoviridae), and rhabdoviruses (Rhabdoviridae). Phylogenetic analysis of the iflaviruses places them within the genus Iflavirus in affinity with other leafhopper-associated iflaviruses. The five-segmented and highly divergent orthomyxo-like virus showed a relationship with other insect associated orthomyxo-like viruses. The rhabdo virus is related to a leafhopper-associated rhabdo-like virus. Furthermore, the beny-like virus belonged to a cluster of insect-associated beny-like viruses, while the bi-segmented bunya-like virus was related with other bi-segmented insect-associated bunya-like viruses. These results highlight the existence of a complex virome linked to D. maidis and paves the way for future studies investigating the ecological roles, evolutionary dynamics, and potential biocontrol applications of these viruses on the D. maidis-maize pathosystem.

The metabarcoding of Grubs: Traditional herbal medicine of Scarabaeidae larvae

Grubs, called Qicao in China, have a long tradition as herbal medicine in East Asia. These larvae belong to the diverse family Scarabaeidae and are typically harvested from the wild during their immature stage based on morphological characteristics. However, rapid and accurate identification becomes challenging when relying solely on external morphological features, as the lack of clarity on biological sources raises safety concerns for clinical applications. The application of DNA metabarcoding provides a solution by enabling the determination of the biological source of a large sample. In the current study, we collected 19 batches of Grubs, consisting of 11,539 individuals, from the market and analyzed their biological composition through metabarcoding. We identified 49 Amplicon Sequence Variants (ASVs), 21 of which were Grubs. The 21 ASVs were classified into seven Molecular Operational Taxonomic Units (MOTUs) through species delimitation, which revealed that commercially available Grubs are predominantly sourced from Protaetia brevitarsis seulensis, while species of Rutelinae, Anomala, and Holotrichia were also abundant in some commercial batches. Among the identified ASVs, 28 belonged to non-Grub species and indicated adulteration from different animal families; high abundances of these ASVs were detected for Bombycidae, Tabanidae, and Viviparidae. Our findings underscore the complexity of Grubs' species composition and advocate for a deeper understanding of the wildlife sources contributing to herbal products. This research contributes valuable insights into the molecular identification of Grubs, paving the way for enhanced quality assurance in traditional medicine applications to provide safe and effective medicines for humanity.

Molecular characterization of a novel benyvirus infecting wheat in China

In this study, a novel positive single-stranded RNA (+ ssRNA) virus named wheat yellow stripe associated virus (WYSAV) was identified in wheat plants in China. Molecular characterization revealed that the complete genome of WYSAV is divided into two segments, RNA1 and RNA2, which are 6,460 and 4,935 nucleotides (nt) in length, excluding their respective poly(A) tails. RNA1 contains one large opening reading frame (ORF), encoding a replication-associated protein. RNA2 contains six ORFs, encoding a coat protein (CP), a coat protein readthrough domain protein (CP-RTD), triple gene block protein 1 (TGB1), triple gene block protein 2 (TGB2), triple gene block protein 3 (TGB3), and a cysteine-rich protein (CRP). Phylogenetic analysis showed that WYSAV is related to members of the genus Benyvirus in the family Benyviridae. Thus, WYSAV is proposed to be a new member of the genus Benyvirus. Wheat (Triticum aestivum L.) is one of the most important food crops and ranked third in the world in terms of production, only behind rice and maize [1]. During its growth cycle, wheat faces several biotic and abiotic stresses. Wheat soil-borne virus disease is an important disease that is difficult to control and causes severe yield loss in China each year [2]. The main pathogens causing wheat soil-borne virus disease are Chinese wheat mosaic virus (CWMV) and wheat yellow mosaic virus (WYMV), and their transmission vector is Polymyxa graminis [3-5]. Members of the viral family Benyviridae usually have two to five genomic RNA segments and are transmitted by root-infecting vectors belonging to the family "Plasmodiophoridae". Although few members of the family Benyviridae, of which beet necrotic yellow vein virus is the type member, have been identified [6], several recently identified viruses have been found to be phylogenetically related to benyviruses but are not classified as members of the family Benyviridae. These "unclassified benyviruses" include red clover RNA virus 1, Arceuthobium sichuanense virus 3, Dactylorhiza hatagirea beny-like virus, goji berry chlorosis virus [7], Guiyang benyvirus 1, Guiyang benyvirus 2, Mangifera indica latent virus [8], Rhizoctonia solani beny-like virus 1 [9], Sanya benyvirus 1 [10], and Sclerotium rolfsii beny-like virus 1 [11].In this study, we identified a novel + ssRNA virus in symptomatic leaf samples collected from cultivated wheat in the city of Zhumadian, Henan Province, China. We propose to name this virus "wheat yellow stripe associated virus" (WYSAV), and we have deposited its full-length sequence in the GenBank database under the accession numbers OQ547804 (RNA1) and OQ547805 (RNA2).

Diversity of RNA viruses in agricultural insects

Recent advancements in next-generation sequencing (NGS) technology and bioinformatics tools have revealed a vast array of viral diversity in insects, particularly RNA viruses. However, our current understanding of insect RNA viruses has primarily focused on hematophagous insects due to their medical importance, while research on the viromes of agriculturally relevant insects remains limited. This comprehensive review aims to address the gap by providing an overview of the diversity of RNA viruses in agricultural pests and beneficial insects within the agricultural ecosystem. Based on the NCBI Virus Database, over eight hundred RNA viruses belonging to 39 viral families have been reported in more than three hundred agricultural insect species. These viruses are predominantly found in the insect orders of Hymenoptera, Hemiptera, Thysanoptera, Lepidoptera, Diptera, Coleoptera, and Orthoptera. These findings have significantly enriched our understanding of RNA viral diversity in agricultural insects. While further virome investigations are necessary to expand our knowledge to more insect species, it is crucial to explore the biological roles of these identified RNA viruses within insects in future studies. This review also highlights the limitations and challenges for the effective virus discovery through NGS and their potential solutions, which might facilitate for the development of innovative bioinformatic tools in the future.

Uncovering Plant Virus Species Forming Novel Provisional Taxonomic Units Related to the Family Benyviridae

Based on analyses of recent open-source data, this paper describes novel horizons in the diversity and taxonomy of beny-like viruses infecting hosts of the plant kingdom (Plantae or Archaeplastida). First, our data expand the known host range of the family Benyviridae to include red algae. Second, our phylogenetic analysis suggests that the evolution of this virus family may have involved cross-kingdom host change events and gene recombination/exchanges between distant taxa. Third, the identification of gene blocks encoding known movement proteins in beny-like RNA viruses infecting non-vascular plants confirms other evidence that plant virus genomic RNAs may have acquired movement proteins simultaneously or even prior to the evolutionary emergence of the plant vascular system. Fourth, novel data on plant virus diversity highlight that molecular evolution gave rise to numerous provisional species of land-plant-infecting viruses, which encode no known potential movement genetic systems.